This inventor, relates to a fixing device for fixing an object to a fixing plate by the use of a screw member and to an antenna apparatus using the fixing device.
Recently, a digital radio receiver adapted to receive a satellite wave or a ground wave so as to listen to digital radio broadcasting is put into practical use. The digital radio receiver is mounted to a mobile station. Specifically, the digital radio receiver is adapted to receive a radio wave having a frequency of about 2.3 GHz as a reception wave. The reception wavelength (resonance wavelength) λ is equal to about 128.3 mm. Thus, the digital radio receiver is capable of listening to the digital radio broadcasting.
Thus, the digital radio receiver is a radio receiver adapted to listen to mobile broadcasting. The ground wave is obtained by slightly shifting the frequency of the satellite wave after the satellite wave is received by a ground station, and is re-transmitted with linear polarization.
An antenna for receiving the radio wave is disposed outside the mobile station. In case where the digital radio receiver is mounted to an automobile, the antenna is generally attached to a roof plate of the automobile.
For example, Japanese Utility Model Application Publication (JP-U) No. H5-88007 discloses a mounting structure of an automobile antenna, in which a case containing the antenna can be attached to a mounting member at a desired angle.
In the above-mentioned mounting structure, a cable can be extracted from a cable fitting groove formed on a lower surface of the case to the outside at any desired angle. The mounting member is provided with a fitting hole having four convex portions protruding from a center space, and a plurality of mounting portions formed on one side thereof as bent portions.
However, the above-mentioned mounting structure using the mounting member is disadvantageous in the following respects. The mounting member is provided with a number of mounting screw holes. The case is attached to the mounting member by the use of various kinds of screws, such as a mounting screw, a screw with a hexagonal hole, and so on. Therefore, the number of parts is increased and a mounting operation is complicated. Thus, it is difficult to perform the mounting operation smoothly.